Uneventful insect year seen in Alabama cotton

No news tends to be good news as far as cotton insects are concerned, and that has been the case for most producers in Alabama this year, says Ron Smith, entomologist with the Alabama Cooperative Extension System.

“It has been a rather non-eventful year for most of Alabama and for much of the Cotton Belt,” said Smith during the recent East Alabama Cotton Tour. “We did, however, see quite a significant level of thrips injury earlier this season. The thrips numbers were not that great, but the injury was significant in many fields. It could have been because cotton was not growing off as fast as in some years.”

Tests conducted at Prattville in central Alabama have shown that “no at-planting thrips material is perfect anymore,” says Smith. “Actually, Cruiser beat Temik in our conditions at Prattville. And Gaucho seed treatment beat both Cruiser and Temik as far as how it made the cotton look,” he says.

Moving into the growing season, many suspected a severe plant bug year, says Smith, due primarily to extensive rainfall during May and the rapid growth of wild host plants.

“But that didn’t materialize. We saw a few plant bugs in June, but they didn’t carry over into a field generation in July in many places. So we didn’t do a lot of spraying for plant bugs,” he says.

The plant bug species seen by most growers was the tarnished plant bug, notes Smith. This is unlike last year, when the clouded plant bug was the dominant species.

“The stragglers that are now left in fields are primarily the clouded plant bug, but not at any levels that would cause injury,” he says.

As growers moved into July, it was becoming evident, says Smith, that a lot of bollworms were escaping from Bollgard cotton.

“We’ve seen a lot of escaped bollworms in the past two years. It’s all proportionate to the number of bollworms that lay eggs on Bollgard cotton. Bollgard cotton is about 60 percent effective on the bollworm. That goes up to about 80 percent if you have beneficial insects.

“If you spray for plant bugs or stink bugs, and you don’t have them, you’ll see about 40 percent of the corn earworms or bollworms escaping from Bollgard cotton. We’ve seen that in places this year, and they’re at economic levels,” he says.

Alabama cotton producers had a “terrible” stink bug year in 2003, says Smith, and many growers began a preventative spray program, beginning at about mid to late July.

“The program was to spray every two weeks, and that’s what growers have done in south Alabama. As a result, they’ve pretty much whipped back the plant bug populations to where there are no reports of out-of-control stink bug situations. We’ve done a much better job on stink bugs this year. In some places, we might have over done it.”

When speaking about a non-eventful year for cotton insects in Alabama, there is one exception, says Smith. “Since the first of July, growers in Houston and Geneva counties, and in the adjoining areas of the Florida Panhandle and southwest Georgia, have been overwhelmed with worms — bollworms, tobacco budworms, beet armyworms, fall armyworms, soybean loopers and the Southern armyworm.

“They’ve seen every species, and they’ve been fighting them continuously since the first part of July. It has been frustrating for consultants and growers because controls have been less than desirable in some cases, particularly on fall armyworms.”

The problem, says Smith, is that the worms grow to be five to seven days old and get into the bolls before they can be found. By that time, it’s too late, he adds.

“I was in a field in Coffee County that had received four applications in 10 days for fall armyworms. I haven’t seen anything similar since 1977 — where there are multiple fall armyworms on every plant, and 50 percent or more of the bolls had been damaged.”

But, while there have been isolated cases of heavy pressure this year, Smith emphasizes that most of Alabama’s cotton fields have been insect free in 2004. “Most growers have spent the summer looking for insects and never finding them.”